1. Field of the Invention
The present invention relates to a data processing apparatus and data processing method, more specifically, reducing power consumption and an enhancing processing speed by use of a proper operation.
2. Description of the Related Art
In the field of data processing apparatuses, such as printers or copiers, there is a growing need to reduce power consumption in a state where the apparatus does not operate (inactive state). One known approach to the need is a technique for reducing power consumption in an inactive state by decreasing (or interrupting) supplying a power to a main controller controlling a data processing apparatus in the inactive state of the data processing apparatus.
The function of connecting to a network is being embedded in data processing apparatuses as a standard feature. A data processing apparatus capable of connecting to a network can perform various kinds of data processing by receiving data and a command from an information processing apparatus, such as a personal computer, over the network and processing the data and command.
When a technique for reducing power consumption is applied to a data processing apparatus having the function of connecting to a network, a problem arises in which it is difficult for the data processing apparatus to quickly perform processing for data and a command received over the network in its inactive state. For example, a case is discussed where a power supplied to a main controller of the data processing apparatus is made smaller than that in a normal state (or interrupted) in an inactive state of the data processing apparatus. In this case, when the data or command is received over the network in the inactive state, the main controller is not operating. Because of this, the data or command remains unprocessed until the inactive state becomes active in response to restarting of supplying the power to the main controller.
When a technique for reducing power consumption is applied to a data processing apparatus having the function of connecting to a network, another problem arises. That is, if the data processing apparatus frequently receives data or commands, the data processing apparatus returns from an inactive state to an active state, and thus the advantageous effects of reducing power consumption are undesirably small.
There is a known technique of interrupting supplying a power to a main controller in an inactive state of a data processing apparatus while continuing supplying a power to a sub controller to process data or a command received by the sub controller over a network (see, for example, Japanese Patent Laid-Open No. 2006-025212). The technique disclosed in this patent document can achieve both a reduction in power consumption by interrupting supplying a power to a main controller of a data processing apparatus and an enhancement in processing speed for data or a command received over a network by a sub controller performing the processing.
For the technique disclosed in the above-mentioned Japanese Patent Laid-Open No. 2006-025212, a packet pattern that requires the data processing apparatus to return from an inactive state to an active state is stored in advance in a region to which the sub controller can refer, and the sub controller causes the data processing apparatus to return from the inactive state to the active state when a packet pattern received over the network matches the previously stored packet pattern.
However, with the technique disclosed in the above-mentioned Japanese Patent Laid-Open No. 2006-025212, a packet pattern is stored in advance in a region to which the sub controller can refer, so a new packet pattern cannot be registered. Even if registering a new packet pattern is made possible, the number of packet patterns that can be registered depends on the amount of a storage area. Further, even if a new packet pattern can be registered in advance, it is difficult to determine in advance which packet pattern is to be registered in a region to which the sub controller can refer. This is because it is difficult for a user of the data processing apparatus to know in advance what kind of packet pattern is frequently used in accordance with a network environment where the data processing apparatus is placed.